WASHINGTON (AP) – Maryland’s highest court blocked a referendum on Sept. 9 that would have allowed Montgomery County voters to decide whether to keep or overturn a new transgender rights law.

The Court of Appeals decision reverses a lower court ruling that permitted the referendum to be placed on the Nov. 4 ballot.

The law prohibits discrimination based on gender identity in housing, employment, taxi and cable service, and public accommodations. It was signed last year by county executive Isiah Leggett, but was put on hold after opponents collected signatures to force a referendum.

Equality Maryland, a gay and transgender rights group, challenged the petition effort in March. But Circuit Court Judge Robert Greenberg ruled in July the referendum could go forward because the group’s challenge came too late.

In a brief order issued Sept. 9, however, the Court of Appeals reversed the lower court decision. The order came one day after the Annapolis court heard arguments in the case. A full opinion was to be filed later.

The ruling was quickly praised by transgender rights groups.

“No one’s civil rights should ever be put to a vote, and the court’s decision gives meaning to that essential principle,” Human Rights Campaign President Joe Solmonese said in a statement.

The law’s opponents have expressed concerns about privacy – saying they worried male cross-dressers, for instance, would have access to women’s restrooms and health club locker rooms.

But council member Duchy Trachtenberg, who proposed the bill, said laws already exist to prevent people from harassment in public settings, including restrooms.

“I don’t believe this kind of fear-mongering tactic ever belonged on the ballot,” Trachtenberg said. She expects the law to take effect quickly now that the referendum has been blocked.

While disappointed with the ruling, opponents said it was too soon to decide whether they would take additional action.

“It’s fundamentally unfair that a political activist group can step in and stop people from voting,” said Amy Smith, litigation counsel with the Alliance Defense Fund, which has been helping the law’s opponents.

To force a referendum, the group Citizens for Responsible Government was required to gather 25,000 signatures – 5 percent of registered voters. But Equality Maryland argued that number was too low because the elections board failed to count more than 50,000 inactive voters.

Circuit Court Judge Robert Greenberg agreed. But he said Equality Maryland’s challenge should have been filed within 10 days after the elections board accepted the first batch of signatures Feb. 20.

Equality Maryland, however, waited until March 14 – eight days after the board formally certified the referendum.

Jonathan Shurberg, an attorney for Equality Maryland, argued Monday that many residents often aren’t even aware a petition drive is under way until the board grants certification. He said requiring a challenge before then places an unfair burden on would-be challengers.

He said the Sept. 9 ruling “vindicates the right of private citizens to participate in the referendum process and to challenge and test” petitions.